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Our “How Things Work” feature for November 2011 focuses on the landing of the Curiosity Mars Science Laboratory in August 2012. But that will be just the start of this most ambitious Mars mission yet, which is due to launch from Cape Canaveral on November 25. In this animation from NASA’s Jet Propulsion Laboratory, we see Curiosity’s journey from Earth, the dramatic descent to the surface, and glimpses of the kinds of science investigations the car-size rover will conduct during its multi-year stay on Mars.
Video: JPL

Three generations of Mars rovers (two test vehicles and a flight spare) line up in JPL’s robotics test yard: (clockwise from bottom) Sojourner, a Mars Exploration Rover, and Curiosity.
(NASA/JPL/Caltech)

A traffic sign leaves no doubt about JPL’s role in planetary exploration.
(Heather Goss)

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A field geologist and professor at the California Institute of Technology, Grotzinger serves as Curiosity’s lead project scientist. Probably more than anyone else at NASA’s Jet Propulsion Laboratory in Pasadena, California, he knows how much is riding on the $2.5 billion mission, launched last November 26 and expected to arrive on Mars early this month. In these budget-obsessed times, everybody in planetary research—and in Washington—will be closely evaluating the rover’s scientific return.

What if Curiosity is destroyed while attempting to land? What if it smacks down hard and is hobbled, unable to achieve its purpose: to roam as many as 12 miles over 98 weeks—one Martian year—examining rock and soil samples that could reveal whether the Red Planet was capable of sustaining carbon-based life in its wetter and warmer past?

What if Curiosity arrives unscathed at its carefully chosen touchdown site, a crater the size of Connecticut and Rhode Island combined, only to find at the end of its long journey a wasteland devoid of clues that could help answer the eternal question: Are we alone in the universe?

The lanky, erudite Grotzinger, 55, concedes that if life ever existed on Mars, chances of the robot uncovering conclusive evidence of it are slim. The goal seems especially daunting when one realizes how relatively rare ancient fossilized remains are on Earth. For the first two billion years of Earth history, before animals evolved, life stayed at the microbial level. And finding a fossil record of these tiny organisms is “almost like finding a needle in a haystack,” says Grotzinger.

President Obama’s proposed fiscal 2013 budget would slash one-fifth of the $1.5 billion that NASA’s planetary sciences division received in 2012. There is concern in the planetary science community that such a cutback could stall scientific momentum, create a brain drain, and undermine the space agency’s ability to mount future missions on the scale of Curiosity, which JPL personnel refer to as the “Mars Science Lab,” or MSL.

Few have been more openly critical of the current mission than planetary scientist Alan Stern. In 2008, he resigned from NASA after growing frustrated by what he says was overspending on bold but chancy projects like Curiosity, while more modestly priced, equally promising exploratory programs went begging. Says Stern: “Because we bet so much on MSL, it has to work, or it will set back all of planetary science for this decade.”

Others are less dire when forecasting the effects of Curiosity’s success or failure. Former NASA scientist John A. Grant III, a geologist at the National Air and Space Museum’s Center for Earth and Planetary Studies who helped pick Curiosity’s landing site (see “Mars Journal”), asserts that the rover need not deliver fossilized Martian trilobites to prove its worth. Rather, Grant believes that by merely sending back fresh and stunning images of Mars, adding to those taken by its robotic predecessors, Curiosity could help reignite enthusiasm for unmanned space exploration. What would happen if Curiosity hits upon actual organic remains? “If it lands and finds the proverbial dinosaur bone sticking out of the ground,” Grant muses, “the budget situation could change quickly.”

That Curiosity has made it as far as it has is perhaps itself a success, given how many previous efforts never even made it out of Earth orbit. Attempts to visit Mars began with the Soviets’ Korabl 4 in 1960, which never transcended the atmosphere due to a propulsion failure. Of the nearly 40 other Mars missions that have followed, fully two-thirds flopped (see “Occupy Mars”). Spacecraft have blown up on liftoff and fallen from the sky like Icarus. They’ve gone missing en route and upon arrival, as if part of a storyline from “The X-Files.”

Most recently, in January, Russia’s attempt to reassert itself in planetary exploration faltered after its Phobos-Grunt (Phobos-Ground) probe, intended to return soil samples from Mars’ largest moon, Phobos, failed to tug free of Earth’s gravity and lethargically lapped the globe for a couple of months before plunging into the Pacific.